Continuous flow centrifuge having a rotary face seal



y 0, 1965 E. G. PICKELS ETAL 3,195,809

CONTINUOUS FLOW OEN'I'RIEUGE HAVING A ROTARY FACE SEAL Filed March 27, 1962 5 Sheets-Sheet 1 I3\ I I I7 II F/G. 37 I4 28 r l. I 36 3| I 27 32 i 33 I i 26 I I 34 EDWARD G. PICKELS RICHARD C. STALLMAN INVENTORS BY X44 vi F/G. 7 ATTORNEY y 1965 E. e. PICKELS ETAL 3,195,809

CONTINUOUS FLOW OENTRIFUGE HAVING A ROTARY FACE SEAL Filed March 27, 1962 5 Sheets-Sheet 2 EDWARD G. PICKELS RICHARD C. STALLMAN INVENTORS BYWMj/W ATTORNEY y 20, 1965- E. s. PICKELS ETAL. 3,195,809

CONTINUQUSFLOW CENTRIFUGE HAVING A ROTARY FACE SEAL Filed March 27, 1962 I 5 Sheets-Sheet 5 EDWARD e. PICKELS RICHARD c. STALLMAN mmvroks ATTORNEYS y 1965 E; a PICRELS ETAL 3,195,809

con'rmuous FLOW CENTRHUGE- HAVING A ROTARY FACE SEAL Filed March 2'7, 1,962 5 Sheets-Sheet 5 F/G. l2

RICHARD C. STALLMAN INVENTORS ATTORNEYS F/G /3 EDWARD e. PICKELS United States Patent 3,195,809 CONTINUOUS FLOW (IENTRIFUGE HAVING A ROTARY FACE SEAL Edward G. Pickels, Atherton, and Richard C. Stallman, San Carlos, Calif., assignors to Beclrman Instruments, Inc., a corporation of California Filed Mar. 27, 1962, Ser. No. 182,813

1 Claim. or. 233-21 This invention relates generally to a centrifuge and more particularly to a continuous flow centrifuge having a rotary face seal.

In our copending application Serial No. 804,609, filed April 7, 1959, now U.S. Letters Patent 3,073,517, there is described a continuous flow centrifuge apparatus in which the rotor, disposed in a rotor chamber, is supported and driven from the bottom. The fluid to be processed is fed into and removed from the top of the rotor by a stationary fluid feeding and removal assembly which extends into the rotor and is submersed in the fluid. An arrangement of the foregoing type is suitable where the fluids may be exposed to the surrounds.

In copending application Serial No. 94,537, filed March 9, 1961, now U.S. Letters Patent 3,103,489 assigned to the assignee herein, there is shown a continuous flow centrifuge apparatus in which the fluid is fed into and removed from the rotor through a fluid feed and removal shaft assembly which is attached to the rotor for rotation therewith. The connection between the stationary port-ions of the centrifuge system and the rotating flui feed and removal shaft assembly is made through a rotary face seal. The rotary face seal provides means whereby the fluid can be fed between the stationary and rotating parts without danger of contamination or loss of fluid.

It is an object of the present invention to provide a continuous flow centrifuge for operation in vacuum.

It is a further object of the present invention to provide a continuous flow centrifuge including a rotary face seal having a sealing force which is proportional to the pressure of the fluid passing through the same.

It is another object of the present invention to provide an upper bearing and seal assembly which is adapted to support and guide a shaft extending upwardly from the rotor of a centrifuge apparatus.

These and other objects of the present invention will be more clearly apparent from the following description when taken in conjunction with the accompanying drawmgs.

Referring to the drawing:

FIGURE 1 is a side elevational view, partly in section, showing a continuous flow centrifuge apparatus;

FIGURE 2 is an enlarged sectional view of the upper bearing and seal assembly taken generally along the lines 22 of FIGURE 1;

FIGURE 3 is a sectional view taken generally along the line 33 of FIGURE 2;

FIGURE 4 is a sectional View taken generally along the line 4- -4 of FIGURE 2;

FIGURE 5 is an enlarged view, partly in section, showing the centrifuge rotor, feed shaft, and coupling of the shaft to the rotor;

FIGURE 6 is a sectional view showing a modified coupling of the feed shaft to the rotor;

FIGURE 7 is an enlarged view of the rotary face seal employed to feed and remove fluid from a rotating rotor feed shaft;

FIGURE 8 is a sectional view taken along the line 88 of FIGURE 7;

FIGURE 9 is a view taken generally along the line 99 of FIGURE 7; 1 FIGURE 10 is a sectional view taken generally along the line 1010 of FIGURE 5;

3,195,809 Patented July 20, 1965 FIGURE 11 is a view showing the rotary face seal loading assembly;

FIGURE 12 is an elevational view, partly in section, of a modified upper bearing and seal assembly;

FIGURE 13 is an enlarged view taken generally along the line 13-13 of FIGURE 12 and showing the rotary face seal arrangement employed with the upper bearing and seal assembly of FIGURE 12; and

FIGURE 14 is a sectional view taken generally along the line 1414 of FIGURE 4.

Referring to FIGURE 1, the centrifuge apparatus illustrated includes an outer housing 11 which encloses the drive means and rotor housing. The top of the housing 11 is provided with an opening 12 through which the rotor 13 may be passed for mounting within the rotor housing on the drive shaft 14, as will be presently described. A door 15 threadably receives the upper hearing and seal assembly 20. The door 16 is provided with spaced rollers 18 which ride in spaced channels 19 secured to the sides of the housing 11 so that it may be easily opened to provide access to the housing. A latch mechanism (not shown) works in conjunction with controls (not shown) to releasably lock the door 16.

The side walls of the rotor chamber comprise a cylindrical steel member 21 which acts as a guard in the event of breakage or explosion of the rotor under the strains created by the centrifugal forces at the relatively high rotational velocity at which it is operated. The lower end of the member 21 receives the bottom wall 22, likewise made of relatively strong material. Thus, the side walls 21 and bottom wall 22 form a steel guard chamber. The interior of the guard chamber may be provided with refrigeration evaporator coils 23 which serve to refrigerate the interior of the chamber.

A suitable vacuum seal is formed between the bottom wall 22 and the support shaft or spindle 14 which extends upwardly into the chamber to support and drive the rotor.

Preferably, the spindle 14 is made of flexible material and extends downwardly with its lower end journalled in an oil filled bearing assembly 26. The bearing assembly is supported by spaced brackets 27 which extend downwardly from a resiliently mounted base 28. A driven pulley 31 is carried by the spindle or shaft 14 and is driven by a belt 32 which engages the drive pulley 33 of a motor 34. For example, the base 28 may be supported from the platform 36 by springs 37. Means (not shown) may be disposed in the housing for evacuating the chamber 17.

Referring to FIGURE 5, the rotor may include a cylindrical bowl 41 which is threaded at its ends as shown at 42 and 43. The lower end threadably receives a closure member or bottom 44. The bottom includes a well 46 which is adapted to receive the upper end of the spindle. Spaced pins 47 and 48 are adapted to engage accommodating holes formed in the upper end of the spindle to provide a positive drive between the spindle and the bottom 44 whereby the rotor can be driven.

The upper end of the bottom 44 is provided with a boss 45 which is adapted to receive a rotor core 49. The core 49 is provided with holes adapted to receive the upper ends of the pins 47 and 48 whereby it also is positively driven from the drive spindle.

The upper end of the cylindrical rotor bowl 41 is threaded at 42 to threadably receive a top or cover member 52. An O-ring 53 is interposed between the shoulder 54 formed on the bowl 41 and the lower edge of the cover 52. The cover is also provided with a plurality of radially extending conduits 56 which are adapted to communicate with the slots 58 formed on the upper end of the core member 49. Fluid flows along the slots 58 through the conduits 56 to the outer portion of the rotor as indicated by the arrows 59.

eases core 49 includes an outwardly extending hub 61 received within the well 62 formed in V the cover member 52. An O-ring 63'provides a fluid seal between the rim 61 and adjacent member 52. I

The core, membcr'is provided with a plurality'of spaced radially extending openings 71 which are adapted to conductffiuidfrom the chamber formed between th v core and bowl 41 into the axial opening 72 to the fluid removal andfeed assembly to be presently, described.

The cover 52 threadably (74) receives member 7 6' which guides flexible feed and removal shaft assembly 77. The shaft 77 includes an outer tube 78' which includes a concentric hollow member 79. The shaft 77 is supported withinthe member 76 by a bushing 80; Spaced O-rings 81 and 82 provided a seal. The endv of the shaftis received by a head 83. A fluid flow passage 84, formed 1 in the head, provides communication'betweenthe axial core passage '72 and space 85 formed between the outside of outer tube 78 and the head. The outer tube 73 ineludes ports 86 which allow fluid to flow upwardly as indicated by the arrows 87 into the annular space formed between the outer surface of hollow inner conduit or tube 79 and the outer tube 78. Fluid is fed into the headaS- sembly through the tube 79. The lower end of the" tube 79 is placed in communication with passage 89 formed in the head. The passage, 89 serves, in turn, to communicate with theadjacent slots 58 and openings or pas sages 56 previously described- An O-ring seal cooperates rounds at the lowerend of the housing. The housing 107 accommodates a bumper bearing 116. As will be presently described, the bearing 116 does not contact the member 76 unless the rotor excessively vibrates and then only serves as a bumper to limit movement of the shaft.

The sleeve 111 is adapted to have its upper end in engagement with the suppcrt ring '117 which is threadably receive-d by the guide 76 when the bearing and seal assembly are lifted whereby the rotor is lifted out of the chamberthr'ough the threaded opening formed in the door. Thus, when the upper bearing assembly'is removed, the sleeve 111 serves to support the rotor from the flange 1%.

The shaft assembly 77 extends upwardlythrough the opening 118 formed in the support housing 107 through the hole 119formed in the "member 120, through a bearing designated generally by the reference numeral 121.

:The bearing 121 includes a sleeve 122 having an annular recess 123.. A hearing sleeve 124 is. fitted within the between the head and the bottom of shaft assembly 77 a the'central opening 72 formed in the core,,through the passage 84 and through the annulus formed between the tubes 78 and 79.

bearing 121'. The sleeve. cooperates. with the recess to form achamber 125 which receives a coolant for cooling the hearing. I Thus,,the temperature of the bearing can be controlled soas. not to affect sample flowing in the feed and removal assembly. 'Interpos'ed between the sleeve 124 and the shaft is a porous sleeve 12-6 which is oil lubricated through. the tube}12';'.- Thus, the bearing assembly 121 serves to rotatably retain the upper end ofrthe flexible shaft assembly 77, provide lubrication and a vacuum seal between the shaft and the surrounds.

, There is provided a flexible vacuum joint or seal between the members 1137 and'12t) which joint comprises a flexible sleeve 131 which isurged into seating arrangement by acoil spring 132.

and 3, is provided-with radially extending fingers 133,.

eachof the fingers including a stainless steel inset 134. Opposite the inset in the member Hit-there is provided a in the member 107 a stainless steel inset 136. The insets The core 49 is provided with longitudinal slots 94 1 which receive vanes96. The vanes extend'radially outwardly withtheir outer edge in contact with the bowl 41.

The vanes compartmentalize the interior of the rotor mass with respect to the other to reduce mixing. The r compartments also reduce mixing which occurs when' liquid is continuously supplied to and removed from the rotor.

Referringto FIGURE 6 there is shown an alternative arrangement for feeding and removing liquid ,from the rotor. The head 83a is provided with a passage 101 which communicates between the annulus formed between the tubes 78 and 79 the adjacent slot 58. The fluid'is then fed back through the central tube 79. Thus, the 'fluid is .fed into the rotor through the annulus and removed through the central tube.

Referring' now to FIGURE2, the guide member76 exreceived by the door'16, previously described. Support are provided with wells having a greater diameter. than a'support pin 137 which is adaptedto ride within the wells and support the member 120 inspacedrelationship with respect to the member 107 at three spaced points.

A ring 141 is supported from inwardly extending fingers gers of the member 120 are interposed intermediate the l by the ring 141 andby the pins 137 from the member housing 107 is mounted on the flang'e 106 by spaced 1 bolts 108. The lower portion of the housing is recessed i 109 to receive a sleeve 111 which surrounds the member I 76 and. which together'with the'recess 109 serves to ace,

commodate an insulating ring 112. This insulating ring 112 is providedwith a circular groove whichreceivesfan TheO-ring 113, cooperates between the r inwardly extending fingers. Supported from the ring and extending downwardly there are provided spaced rubber members 144 which serve to receive the upper ends of the stainless steel insets 134. I a V It is seen then that the member'12t) is supported'both 197 and yet is given suflicient freedom whereby to accommodate any flexure' lor vibration of the upper shaft ,While still restraining the same;

12 and 7. The seal includes a. first portiorr153 secured tends upwardly through flange 106 which is threadably' I to the tube 79. The portion 153 is provided with a plurality of spaced. passages 154 communicating With an annular groove 155 formed on the .upper face of the same. The annulus formed between the inner. flexible shaft and theouter flexible shaft communicates with these passages. An O.-ring' seal "is provided for sealing the chamber formed between the seal portion 153 and the housing 160., Thetube communicates-with the pas sage 156 formed in the seal portion 153 I The stationary'portion of'the rotary face seal includes an outercylindrical shell 161 which accommodates therein the sealing member 162 and forms in cooperation therewith a cooling chamber adapted to receive a coolant for cooling the rotary sealassembly. The chamber is sealed by the O-ring seals 166 and 167. The seal member 162 forms sealing contact with the rotating portion 153 and is provided with a plurality of passages which extend upwardly and terminate in an annular groove 165 which, in turn, communicates with the passage 168 connected to an exhaust tube 169. The central shaft member 79 communicates with the axial opening 171 which, in turn, communicates with the opening 172 and input tube 173.

The member 162 is urged downwardly into sealing contact by the pressure of the fluid being processed. The seating force is developed by a loading cartridge, shown in detail in FIGURE 11. The cartridge includes a piston member 181 which extends into the cylinders 183 and 184 formed in the pieces 186 and 187. O-rings 188 and 189 form the piston rings. The fluid which flows through the centrifuge is caused to enter into the tube 191, contact the face of the piston 181 and leave through tube 192. The fluid then flows into the rotor and on its return from the rotor, flows into the tube 193 in contact with the other end of the piston 181 and leaves through the tube 194. The fluid pressure tends to expand or force apart the two ends of the sealing assembly. However, the lower end 186 engages a ball which, in turn, engages the member 175 urging the same downwardly so that the stationary seal face is urged into sealing engagement with the rotating seal face. The upper member 187 engages a ball 198 which is engaged by an adjustable screw 199 extending downwardly through the housing 201 which houses the upper bearing and seal assembly.

An insulated cover is placed over the complete assembly. The cover may include insulating material 200 such as styrofoam secured to a shell 202. The shell may be separated into two portions and hinged at 203, FIGURE 4. The shell may include inlet and outlet coaxial pipes 204 and 205 for supplying the fluid being separated and the coolants into the housing as schematically illustrated in FIGURES 2 and 4.

The bearing and seal assembly includes means for washing the rotary face seal while operating and such means may include a jet 206 which serves to spray water onto the rotary face seal. The water leaving the face seal flows downwardly between the parts and out through an outlet 207 which also serves as the outlet for other fluids which may leak into the assembly.

Thus, it is seen that there is provided a bearing and seal assembly which serves to form a portion of the vacuum enclosure for the rotor and which, in turn, supports the flexible shaft extending upwardly. The assembly includes means for assuring that the force of the rotary face seal is comparable to the pressure of the liquid whereby leakage is minimized. Places where heat is generated or which are in contact with the fluid are cooled whereby the same may be maintained at substantially the temperature of the fluid to prevent damage or decomposition of the same. The complete assembly supports the shaft in such a manner that it may flex to accommodate vibrations in the self-balancing rotor due to unevenness in loading or to flutter in the liquid being separated. The resilient mounting aids in damping out vibrations which may occur. The assembly permits the feed and removal of fluids at atmospheric pressure into a rotor which is disposed for rotation in a vacuum chamber.

In certain instances, it may be desired to more rigidly support the upper shaft and to provide different inlet and outlet passages. Referring to FIGURES 12 and 13, there is illustrated a modified assembly. Parts in FIGURES 12 and 13 bear the same reference numerals as like parts described with reference to the previous figures. The member 76a serves to receive a rigid shaft 211 which extends upwardly and is suitably sealed to the sleeve 212 as, for example, O-rings 213. A plurality of passages 214 are provided on the member 212 and communicate with the space 216 which, in turn, communicates with the openings 154a in the rotating rotary seal portion 153a. The inner shaft is suitably secured to the rotating seal portion 153a, as, for example, by a seal member 215. The shaft 7% extends downwardly into the head as previously described. The rigid shaft 211 and the flexible shaft 79a cooperate to form inlet and outlet passages. The annulus serves as one passage and the hollow shaft 79a serves as the other passage. The bearing arrangement is simi lar to that previously described. However, the member 219 is rigidly secured to a rigid ring 149a and the flexibility is provided by a rubber bushing 221 interposed between the bearing member 122 and the support member 219.

In all other respects, the assembly is substantially like that described above and bears like reference numerals.

We claim:

A centrifuge including a rotor, means engaging the bottom of said rotor to support and drive the same, a fluid feed and removal shaft assembly secured to the upper end of said rotor and adapted to rotate therewith, said fluid feed and removal shaft assembly including an axial passage and an annular passage surrounding the same, a stationary face seal member, stationary fluid feed and re moval lines, fluid passages formed through said stationary member in fluid communication with said lines, a rotary face seal member secured to and in fluid communication with the upper end of said shaft and comprising a rotatable face member making sliding contact with said stationary member and providing fluid communication between said axial and annular passages and stationary fluid feed and removal lines, and fluid pressure means for axially urging said rotary face member and said stationary member into pressurized sealing contact with one another, said means including means defining a pair of spaced apart cylinders, means connecting one of said cylinders in fluid pressure communication with said stationary fluid feed line, means connecting the other of said cylinders in fluid pressure communication with said stationary fluid removal line, a piston extending into and between said cylinders and responsive to the fluid pressure in said cylinders, stationary means in engagement with one of said cylinders, the other of said cylinders being in engagement with said stationary member, whereby the sealing contact between the rotary face member and the stationary member is responsive to the fluid pressure in the cylinders and in the stationary fluid feed and removal lines.

References Cited by the Examiner UNITED STATES PATENTS 399,114 3/89 Adams et al.

496,120 4/93 Hart 233-44 672,4-94 4/01 Robertson et a1.

732,886 7/03 Odell et al. 233-21 1,161,839 11/15 Burtch 233-21 X 1,174,955 3/ 16 Balzer.

2,240,141 4/ 41 Lindgren.

2,536,793 l/51 Andersson et al.

2,551,621 5/51 Michelson 308-143 X 2,605,045 7/52 Strezynski.

2,906,449 9/59 Sullivan.

2,932,975 4/60 Racz 233-23 X 3,061,181 10/62 Gooch 233-23 X 3,069,016 12/62 Kiesskalt et al 233-23 X 3,073,517 1/63 Pickels et al 233-22 X 3,097,167 7/63 Beyerle.

3,103,489 9/ 63 Pickels 233-28 X 3,126,338 3/64 Steinacker 233-23 HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, ROBERT F. BURNETT,

Examiners. 

